Najicablitz626
I would say if you add more kamen riders keep them in his age range it will be weird to have a older person as a kamen rider for example cap is a season leader if you made him a rider the spot light would be more on him then the Mc where as if you brought original characters or made Ned or mj a rider it would fit since they may be a side character but they are perfect secondary or a tertiary rider
if you still looking for New Riders how about Bruce Banner and his assistant I know he's the Hulk but why not give him the double driver his assistant can wear the main suit and watch out for the Hulk but for Peter and Uncle Ben how about the build Duo for obvious reasons the colors lol finally before I forget isn't there like three more riders you can get from the riders world o two from drive the third Rider and one antagonist that turned Hero at the end, not to mention Mr belt you only have to give him a robot body, from ooo's you should have the coin, the last one I could think of is from fourze weren't one of the main characters a switch?